Search

Your search keyword '"Urano, Chiharu"' showing total 90 results
Start Over Author "Urano, Chiharu"
90 results on '"Urano, Chiharu"'

1. An Electronic Measurement of the Boltzmann Constant

Author

Benz, Samuel P., Pollarolo, Alessio, Qu, Jifeng, Rogalla, Horst, Urano, Chiharu, Tew, Weston L., Dresselhaus, Paul D., and White, D. Rod

Subjects
Condensed Matter - Superconductivity
Abstract

The Boltzmann constant was measured by comparing the Johnson noise of a resistor at the triple point of water with a quantum-based voltage reference signal generated with a superconducting Josephson-junction waveform synthesizer. The measured value of k = 1.380651(18) \times 10^-23 J/K is consistent with the current CODATA value and the combined uncertainties. This is our first measurement of k with this electronic technique, and the first noise thermometry measurement to achieve a relative combined uncertainty of 13 parts in 10^6. We describe the most recent improvements to our Johnson Noise Thermometer that enabled the statistical uncertainty contribution to be reduced to seven parts in 10^6, as well as the further reduction of spurious systematic errors and EMI effects. The uncertainty budget for this measurement is discussed in detail., Comment: 23 pages, 7 figures

Published
2010
Full Text
View/download PDF

4. Progress on the BIPM watt balance

Author

Picard, Alain, Hao Fang, Kiss, Adrien, de Mirandes, Estefania, Stock, Michael, and Urano, Chiharu

Subjects
Voltage -- Measurement, Magnetic fields -- Analysis
Published
2009

5. Operation of Josephson junction with current pulses generated by triggering a cold photo detector with an optical comb

Author

Urano, Chiharu, Kaneko, Nobuhisa, Maezawa, Masaaki, Gorwadkar, Sucheta, Itatani, Taro, Saitou, Hiroshi, Maeda, Johi, and Kiryu, Shogo

Subjects
Josephson junction -- Design and construction, Superconductive devices -- Design and construction, Voltage -- Measurement, Business, Electronics, Electronics and electrical industries
Abstract

The experimental results on a Josephson junction array (JJA) driven by current pulse trains generated by triggering a photo detector located in a cryostat with an optical comb is reported.

Published
2007

10. A precise evaluation of NbN-based 1-V programmable Josephson voltage standard arrays

Author

Urano, Chiharu, Murayama, Yasushi, Iwasa, Akio, Shoji, Akira, Yamamori, Hirotake, and Ishizaki, Mayumi

Subjects
Electric circuits -- Design and construction, Electric circuits -- Properties, Electric circuits -- Standards, Voltmeter -- Design and construction, Voltmeter -- Properties, Voltmeter -- Standards
Published
2005

18. スピネル型酸化物LiV_2O_4の重い電子挙動 : 異常な輸送現象と幾何学的フラストレーションの役割(<特集>低次元量子スピン系(無機系・実験)の最近の展開2)

Author

Urano, Chiharu and Takagi, Hidenori

Abstract

スピネル型酸化物LiV_2O_4において低温で有効質量の増大したフェルミ液体的な振舞いが見られることが、水熱法により合成された単結晶を用いた輸送現象および比熱の測定から確認された。コヒーレンス温度T^*～20-30Kより下の温度におけるさまざまな物理量の変化は重い電子挙動を示す希土類化合物と極めて類似している。T>>T^*における電気抵抗の温度変化、電気抵抗の圧力効果、およびLi_xZn_V_2O_4の比熱からLiV_2O_4における重い電子状態形成の起源について議論する。, この論文は国立情報学研究所の電子図書館事業により電子化されました。

Published
2001

22. Johnson Noise Thermometry Based On Integrated Quantum Voltage Noise Source

Author

Urano, Chiharu, primary, Yamada, Takahiro, additional, Maezawa, Masaaki, additional, Yamazawa, Kazuaki, additional, Okazaki, Yuma, additional, Fukuyama, Yasuhiro, additional, Kaneko, Nobu-hisa, additional, Yamamori, Hirotake, additional, Maruyama, Michitaka, additional, Domae, Atsushi, additional, Tamba, Jun, additional, Yoshida, Shunsuke, additional, and Kiryu, Shogo, additional

Published
2016
Full Text
View/download PDF

38. Design and Fabrication of Integrated Cryogenic Current Comparators

Author

Maezawa, Masaaki, primary, Urano, Chiharu, additional, Maruyama, Michitaka, additional, Yamada, Takahiro, additional, Oe, Takehiko, additional, Hidaka, Mutsuo, additional, Satoh, Tetsuro, additional, Nagasawa, Shuichi, additional, Hinode, Kenji, additional, Kiryu, Shogo, additional, and Kaneko, Nobu-hisa, additional

Published
2011
Full Text
View/download PDF

43. Operation of a Josephson arbitrary waveform synthesizer with optical data input

Author

Urano, Chiharu, primary, Maruyama, Michitaka, additional, Kaneko, Nobu-hisa, additional, Yamamori, Hirotake, additional, Shoji, Akira, additional, Maezawa, Masaaki, additional, Hashimoto, Yoshihito, additional, Suzuki, Hideo, additional, Nagasawa, Shuichi, additional, Satoh, Tetsuro, additional, Hidaka, Mutsuo, additional, and Kiryu, Shogo, additional

Published
2009
Full Text
View/download PDF

46. Calibration System for Zener Voltage Standards Using a 10 V Programmable Josephson Voltage Standard at NMIJ.

Author

Maruyama, Michitaka, Iwasa, Akio, Yamamori, Hirotake, Chen, Shih-Fang, Urano, Chiharu, and Kaneko, Nobu-hisa

Subjects
ZENER effect, JOSEPHSON effect, ELECTRIC potential, LIQUID helium, CALIBRATION
Abstract

We have developed a calibration system for the Zener voltage standards using a programmable Josephson voltage standard (PJVS) for liquid-helium consumption reduction and improvement in the calibration performance. The PJVS array is composed of 524 288 niobium nitride (NbN)-based overdamped Josephson junctions and is cooled by a 10-K compact cooler. To verify the validity of the system, indirect and direct comparisons of the PJVS system and our conventional Josephson voltage standard system have been carried out. As a result, an agreement within a relative expanded uncertainty of 8.4\times 10^-10 was obtained for a nominal voltage of 10 V. We also discuss the uncertainty sources in the calibration of the Zener voltage standards using our PJVS system. [ABSTRACT FROM PUBLISHER]

Published
2015
Full Text
View/download PDF

48. Optimization of \Mn3\Ag1 - x \Cux\N Antiperovskite Compound Fabrication for Resistance Standard.

Author

Oe, Takehiko, Urano, Chiharu, Hadano, Motoyoshi, Ozawa, Atsushi, Takenaka, Koshi, and Kaneko, Nobu-hisa

Subjects
*MANGANESE nitrides, *TEMPERATURE coefficient of electric resistance, *ELECTRIC resistors, *PROCESS optimization, *ANNEALING of metals
Abstract

We performed a detailed evaluation of the temperature coefficient of resistance of manganese nitride antiperovskite compounds, i.e., \Mn3\Ag1 - x\Cux \N, around 23 ^\circ\C. The second-order term of the temperature coefficient \beta was found to show a rough correlation with the Cu content. For a Cu content x = 0.4, the compound \Mn3\Ag0.6\Cu0.4 \N shows the lowest temperature coefficients. The drift rate of the samples was also investigated. The drift rate was suppressed to about 1/30 by higher temperature annealing, and the lowest drift rate was 9.1 (\mu\Omega/\Omega)/year. We expect that this antiperovskite compound will be useful for precision resistors and improve the temperature coefficient of resistors by process optimization so that they can be used to produce standard resistors for example. [ABSTRACT FROM PUBLISHER]

Published
2013
Full Text
View/download PDF

Catalog

Books, media, physical & digital resources
See catalog results